Help! My A4000 has only 4.7V!

[spirantho]

Can anyone help with this? I've recapped the board as it was having trouble.. but it's still having trouble. Used two different new ATX PSUs via an AmigaKit adaptor.. but it's only 4.7V on the +5V line, which means it most of the time doesn't boot up.

This is with any hardware on board, by the way (not even a CPU card sometimes!).

Does anyone have any suggestions? I'm just recapping the board... again....

[spirantho]

I've checked three PSUs now - the Corsair CX430, the Powercool 450W modular one (not a cheap one), and a little Atlas 350W one from my Peg-II. All of them run low, and there's large ripple on the 5V line and, I believe, on the -12V line. The voltage isn't constant, it tends to bounce around a lot on the -12V line especially. On the +5V line there's a large ripple and the voltage slowly decreases. It was at 4.58V at one point.

I'm measuring on the end of one of the caps (C188, by the SIMM sockets) and on one of the ICs.

Edit: the +5V wire on the ATX adaptor was getting hot before, as the AmigaKit adaptor only has one wire for the +5V and I think it was too much when loaded with the CSPPC etc.. I therefore soldered one of the other +5V wires from the ATX socket on the adaptor directly to the +5V pin on the underside of the socket, so I know it's a good connection.

[spirantho]

Thanks for the link but I can't see that 3 PSUs can be bad with it! I haven't used my original 4000 PSU for years as I towered it, wonder if I still have the 200W PSU I used for ages... but I think that may have died.